U.S. Pat. No. 4,834,673 discloses a transition adapter which is secured onto a flat power cable by being crimped thereto, and the adapter includes one or more contact sections to be engaged with corresponding contacts of an electrical connector to transmit power from the cable to the connector. The cable is of the type entering commercial use for transmitting electrical power of for example 75 amperes nominal, and includes a flat conductor one inch wide and about 0.020 inches thick with an extruded insulated coating of about 0.004 to 0.008 inches thick over each surface with the cable having a total thickness averaging about 0.034 inches. The metal of the flat conductor is for example of Copper Alloy 110 and the insulation is for example TEFZEL thermoplastic resin known as polyethylene-co-tetrafluoro-ethylene copolymer (trademark of the E. I. DuPont de Nemours and Company, Wilmington, Del.).
The transition adapter of U.S. Pat. No. 4,834,673 includes a pair of plate sections hinged together at the forward or terminal end of the adapter, and a still-insulated end or edge portion of the cable is to be crimped therebetween. At a selected location forwardly of the cable-crimping region at least one of the plate sections is bent at an angle away from the other so that the plate sections are facing each other at an angle and are thus spaced apart to receive the cable end or edge therebetween. A plurality of lances extend from one plate section toward corresponding apertures in the other so that upon pressing the plate sections together the lances penetrate through the cable. The lances are then received through the apertures and the ends thereof are bent over and against the outer surface of the other plate section, being bent over by tool means or by being curled around by integral arcuate guides at each aperture. By penetrating the cable a plurality of electrical connections are formed between the adapter and sheared conductor edges of the cable. By being stamped from sheet metal of an appropriate alloy, the lances are preferably defined by shear edges and penetrate through the insulation and also the conductor of the cable in cooperation with the lance-receiving apertures which preferably include at least one shear edge against which the cable is pressed during penetration by the lances. Additional electrical connections are made by a plurality of barbs which penetrate the cable insulation to engage and bite into the cable conductor.
It is desirable to provide an adapter having means for shearing through a flat power cable conductor at a plurality of locations and for providing a plurality of electrical connections between the adapter and the cable conductor wherein the connections are and remain gas-tight by reason of stored energy.
It is also desirable to provide each gas-tight connection with substantial surface area of engagement between the adapter and the cable's conductor.
It is still further desirable to provide an adapter with a portion being of a metal alloy capable of assuming a shape upon termination to the cable which maximizes surface area engagement with the sheared edges of the cable conductor while retaining stored energy to maintain the gas-tight nature of the connections during long-term in-service use.
The adapter of U.S. Pat. No. 4,867,700 is crimpable to a flat power cable by penetrating the insulation covering the cable's conductor and also shearing through the conductor at a plurality of locations. The adapter has a body member stamped and formed of sheet metal and has a pair of opposed plate sections each having at least one terminating region transversely thereacross, with the terminating regions of the opposed plate sections being associated in opposing pairs. Each terminating region of the pair is formed of alternating wave shapes and relief recesses, and the plurality of wave shapes of one plate section extend toward the other plate section and are spaced from each other by the relief recesses, with the wave shapes of one plate section corresponding with the relief recesses of the other. Each wave shape includes a transverse radiussed crest extending between parallel axially aligned shearing edges which are perpendicular with respect to the crest. Essentially the wave shapes of one plate section would intermesh with those of the other if urged toward each other, but preferably essentially with zero clearance.
The transition adapter is terminated to a cable disposed between the plate sections, by the preferably hingedly joined plate sections being pressed tightly together with the cable therebetween. Each wave shape will be forced against an adjacent surface portion of the cable and its crest will deflect that adjacent surface portion of the cable out of the plane of the cable and will stretch the conductor portion thus deflected. Simultaneously, the shearing edges of that wave shape cooperate with the shearing edges of the adjacent wave shapes of the opposed plate section: the shearing edges are aligned under zero clearance and pair up so that when the wave shapes are forced against the opposite surface of the cable, the paired shearing edges penetrate and tear the insulating layers and shear the conductor perpendicularly to the wave crest. Preferably an arcuate relief shape is formed at each relief recess extending away from the other plate section, and each wave shape is received into a corresponding opposed relief recess with the crest-deflected cable portion disposed between the wave's crest and the inner surface of the opposed arcuate relief shape. Portions of each shearing edge of the wave shapes of one plate section of the adapter engage newly formed edges of the cable conductor sheared by the adjacent wave shapes of the other plate section. The cable conductor is sheared at a plurality of locations for axial shear lengths of for example 0.25 inches and substantially without great bulk deformation of the metal thereof during the shearing process. Also since the shearing is axial with respect to the cable when the adapter is terminated on an end of the cable, the cable is not materially weakened. Essentially the intermeshing adapter wave shapes form a plurality of interlocking wave joints with the cable conductor thus defining a strong termination transversely across the cable, with the opposing plate sections acting as a zero clearance tool and die which will resist opening thereafter.
In the first embodiment of the adapter of U.S. Pat. No. 4,867,700 a pair of malleable, high copper content insert members are affixed to and predisposed against the outwardly facing surfaces of the respective plate sections of the stamped and formed adapter body member, along and across the terminating or wave regions thereof. Each insert member is shaped to conform to the wave region of the associated plate section by having conforming wave shapes and by having apertures within which the arcuate relief shapes are disposed. The insert members are adapted to establish the primary electrical connections to the cable conductor, while the transition adapter body member provides the strong mechanical means of attachment to the cable.
It is desirable to provide a method for assuring the integrity of the electrical connections between the insert members and the exposed sheared conductor edges.
It is also desirable to provide a method for assuring the securing of the insert members to completed termination.
It is further desirable to provide a method for affixing the insert members to the transition adapter body member prior to cable termination.